Natural Wood Substrates for Flexible Thin-Film Temperature Sensors

This study explores nature-based substrates as sustainable alternatives to traditional polymer-based materials for unobtrusive and flexible electronics. It focuses on the fabrication of thin-film temperature sensors directly on thin walnut wood substrates. This natural material combines mechanical flexibility, sustainability, and aesthetics. Metallic resistive temperature detectors (RTDs) and thermistors based on semiconducting Indium Gallium Zinc Oxide (IGZO) were fabricated by sputtering. Despite the high surface roughness of the substrate ($>40 \mu \mathrm{m}$), both types of sensors exhibit functionality, with sensitivities up to 0.259% ° C⁻¹ and stability over multiple temperature cycles. Furthermore, RTDs were bent to radii as small as 23 mm.